Alister Crowley was heavily into the Occult.
I don't know much about him, but do a search in Yahoo or whatever. You will find some info on him.

I know Jimmy Page was a fan of Alister Crowley, I heard he bought his home at one point, but I don't know if that is fact or not.

A funny thing: When I used to do cable TV construction in new housing developments, I did a job at a new development and there were two streets in the development that were named Alister and the next street was named Crowley.
Wicked!

Jimmy Page, of the rock group Led Zeppelin, who owned one of the largest occult bookstores in England, had purchased the mansion of Edward Alister Crowley(1875-1947), one of the most famous Satanists of all time, who called himself "the most wickedest man in the world." The home is said to be inhabited by demons. Page referred to Crowley as an "unrecognized genius of twentieth century thinking." Band member, Robert Plant, who wrote the song "Stairway to Heaven," was also interested in the occult and said that the song just came together, as if he was being driven by some "spiritual force." He said: "Somebody pushed my pen, I think." It became one of the biggest selling records in music history, and is still one of the most requested songs on rock format radio stations. Some of the words, typical of witch language, having a double-meaning. The line: "And when you wind on down the road, the shadow's taller than your soul," means that Satan is supposed to be stronger than us(which, of course, he isn't). Page said it was taken from the writings of a Druid priest, hundreds of years ago, which was based on the Bible. Which Bible?

ah,, good ole' Crowley. This dude used to channel "spirits" thru his wives (i think he had 5? I believe all of them committed suicide too), so he could "capture" the "magick". Apparently he wasn't a "Satanist",, he felt he was much higher along the occultic food chain than that. However, he used the proverb "Do as thou wilt shall be the whole of the law" in his own life. I remember reading of one incident where one of his wives became "possessed" at some sort of museum, leading Crowley to museum piece number 666, which pleased him greatly,, as it was a number he "had always felt connected to".

I'm a Christian, not an occultist, and I have read some of his so called "works" just to see what the dude was about,, my advice is to stay far away from him and any other similar works (Necronomicon, witchcraft, etc...). I had one of the most terrifying physical and mental experiences of my life while reading some of his passages.